- Find out how frequently your store's spices are restocked or visit specialty spice shops, which carefully monitor freshness. Many spices have traveled around the globe; you don't want to buy ones that have aged further on supermarket shelves.
- Make sure spices are properly rotated in bulk bins. "If the bins are never empty, it may mean the store is just filling them from the top," says Hill. If that's the case, some spices could be quite old.
- Taste the product, if possible. Let your palate decide if the spice is fresh.
- Buy smaller amounts of spices more frequently.
- Buy spices whole. Grinding them yourself as needed—with a coffee grinder or a mortar and pestle—gives you maximum flavor.
- Compare newly bought and existing spices side by side. Your new spices should smell and taste stronger. Because essential oils deplete gradually, aroma and flavor loss can be difficult to detect.
- Keep your spices in airtight containers, as air carries away their volatile compounds. Jars with rubber gaskets and latch closures are ideal. Test your jars by submerging them, empty and closed, under water for a half hour. If water has seeped in, replace the gaskets.
- Store your spices in a cool, dry place, as light and heat compromise essential oils. Do not freeze them.
- Know how long spices last. Whole spices like nutmeg and peppercorns keep for up to six to 12 months. Ground spices like chili and curry powders are good for three to six months, as are dried herbs like oregano and basil.
- Test the freshness of herbs by rubbing them between your palms. "You should get a burst of aroma," says Hill. "If you don't smell anything, you're just adding a green powder to your food."
- Change the herbs and spices on your rack every time you change the battery in your smoke detector: That's every six months, says Hill.